When light of frequency twice the threshold frequency is incident on the metal plate, the maximum velocity of emitted electron is v 1 . When the frequency of incident radiation is increased to five ti

Question

When light of frequency twice the threshold frequency is incident on the metal plate, the maximum velocity of emitted electron is v 1 . When the frequency of incident radiation is increased to five times the threshold value, the maximum velocity of emitted electron becomes v 2 . If v 2 = x v 1 , the value of x will be _____ .

TestHub · Accepted Answer

Maximum kinetic energy is expressed as K max = h f - ϕ , here, ϕ is work function of metal. For first case, 1 2 m v 1 2 = h 2 f 0 − f 0 For second case, 1 2 m v 2 2 = h 5 f 0 − f 0 ⇒ v 2 2 v 1 2 = 4 1 ⇒ v 2 v 1 = 2

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